1. Field of the Invention
The present invention relates to engine start systems including multiple control devices.
2. Description of the Related Art
Recently, vehicles having an idling reduction control device have become widely available so as to reduce a fuel consumption of a vehicle.
In a vehicle having the idling reduction control device, a starter motor is frequently driven so as to restart the internal combustion engine (hereinafter, the engine) of the vehicle. Further, the starter motor is requested to have a quick start capability when the internal combustion engine is restarted after an engine stop caused by the idling reduction control device. To satisfy the quick restart request, there have been proposed various types of starter motors and engine restart techniques.
For example, a patent document 1 as a conventional technique, Japanese patent No. 4068685 has disclosed a control system including a rotating electrical machine and a starter motor as an engine restart device. The control system instructs the engine to be restart by using both the starter motor and the rotating electrical machine which cooperate together.
When the engine is restarted by using both the starter motor and the rotating electrical machine which are in cooperation with each other, it is necessary to operate the starter motor and the rotating electrical machine simultaneously without causing a control-time lag between them. For example, when multiple control devices mounted on a vehicle instruct the starter motor and the rotating electrical machine to operate, it is necessary to execute a synchronous control between the multiple control devices without generating a communication delay. However, the conventional techniques have not provided a correct control method to eliminate such a communication delay between the multiple control devices.